introduction of die casting process casting.pdf · introduction of die ... to typical machining...

Introduction of Die Casting Process

Taizhou Sanjian Mould Co.,Ltdwww.sino-diecasting.com

Editor: Sanjian

Die casting is a metal casting process that is characterized by forcing molten metal under high pressure into a mould cavity, which is created using two hardened tool steel dies which have been machined into shape and work similarly to an injection mold during the process. Most die castings are made from non-ferrous metals, specifically zinc, copper, aluminium, magnesium, lead, pewter and tin based alloys.

The casting equipment and the metal dies represent large capital costs and this tends to limit the process to high volume production. Manufacture of parts using die casting is relatively simple, involving only four main steps, which keeps the incremental cost per item low. It is especially suited for a large quantity of small to medium sized castings, which is why die casting produces more castings than any other casting process. Die castings are characterized by a very good surface finish and dimensional consistency.

Two variants are pore-free die casting, which is used to eliminate gas porosity defects; and direct injection die casting, which is used with zinc castings to reduce scrap and increase yield.

Sanjian is a professional die casting mould producer since we have advanced software to assist us in the designing process and skilled personels who are in the position for decades.

What is Die Casting


The Brief History of Die casting

Die casting equipment was invented in 1838 for the purpose of producing movable type for the printing industry. The first die casting-related patent was granted in 1849 for a small hand operated machine for the purpose of mechanized printing type production. In 1885, Otto Mergenthaler invented the linotype machine, an automated type casting device which became the prominent type of equipment in the publishing industry. Other applications grew rapidly, with die casting facilitating the growth of consumer goods and appliances by making affordable the production of intricate parts in high volumes.

In 1966, General Motors released the acurad process.


There are two basic types of die casting machines: hot-chamber machines and cold-chamber machines. These are rated by how much clamping force they can apply. Typical ratings are between 2,500 and 25,000 kg.

Hot-chamber machines

Hot-chamber machines, also known as gooseneck machines, rely on a pool of molten metal to feed the die. At the beginning of the cycle the piston of the machine is retracted, which allows the molten metal to fill the "gooseneck". The pneumatic or hydraulic powered piston then forces this metal out of the gooseneck into the die. The advantages of this system include fast cycle times (approximately 15 cycles a minute) and the convenience of melting the metal in the casting machine. The disadvantages of this system are that high-melting point metals cannot be utilized and aluminium cannot be used because it picks up some of the iron while in the molten pool. Due to this, hot-chamber machines are primarily used with zinc, tin, and lead based alloys.

Cold-chamber machines

These are used when the casting alloy cannot be used in hot-chamber machines; these include aluminium, zinc alloys with a large composition of aluminium, magnesium and copper. The process for these machines start with melting the metal in a separate furnace. Then a precise amount of molten metal is transported to the cold-chamber machine where it is fed into an unheated shot chamber (or injection cylinder). This shot is then driven into the die by a hydraulic or mechanical piston. This biggest disadvantage of this system is the slower cycle time due to the need to transfer the molten metal from the furnace to the cold-chamber machine.

Casting Equipment


Die casting is accurate and detailed. Because the die casting process offers many advantages that machined parts cannot. It is a less expensive option due to rapid production rates and the fact that material is only utilized where it is needed and only as much as is required. It provides a good mix of mechanical properties, surface finish, and dimensional consistency, which provides a better product at a lower cost.

Not only is die casting a more reliable option, it offers a significant opportunity for cost savings. These savings could be 80% or more compared to typical machining costs. In addition, die casting provides a major reduction in cycle time. For example, a part might cast once every 60 seconds, while the machining process produces two to five parts an hour.

Die casting designs require draft angles and radii to be incorporated into the final design. Therefore, it's important to work with a die caster early during this phase. One of the key benefits of die cast designs is the fact that this process allows you to have a wall thickness of about 2.5mm or less while still having outstanding tensile strength.

Another benefit of die casting is the exceptional repeatability over a long useable life. The die casting process can produce 100,00 or more of identical castings within specific tolerances before additional tooling may be required. Even when replacement is eventually required, the entire die does not necessarily need to be replaced. Often only specific sections need to be replaced or repaired.

Advantages of Die Casting


Die casting is one of the fastest and most cost-effective methods for producing a wide range of components. However, to achieve maximum benefits from the process, it is critical that designers collaborate with the die caster at an early stage of the product design and development. Consulting with the die caster during the design phase will help resolve issues affecting tooling and production, while identifying the various exchanges that could affect overall costs.

For instance, parts having external undercuts or projections on sidewalls often require dies with slides. Slides increase the cost of the tooling, but may result in reduced metal use, uniform casting wall thickness or other advantages. These savings may offset the cost of tooling, depending upon the production quantities, providing overall economies.

Many sources are available for information on die casting design, including textbooks, technical papers, trade journals and professional associations. While the section is not intended to provide a comprehensive review of all the factors involving die casting design, it will highlight some of the primary considerations.

How Can We Design Die Casting Mould


Casting process can be divided into two catogories:

First, a gravity casting: sand casting, die casting. The molten metal gravity poured into the cavity.

Second, pressure casting consists of low pressure casting and high pressure casting. It relies on the additional pressure onto the molten metal casting cavity moment.

Casting process typically include:

1. Mold preparation (casting the liquid metal to be a solid container)Mold, according to the materials, can be divided into sand, metallic, ceramic, clay type, graphite, etc.; according to the number of use times, it can be divided into semi-permanent and permanent style. The merit of mold preparation is a major factor affecting the quality of castings.

2. Cast metal melting and castingThere are all kinds of cast iron, cast steel and cast non-ferrous metals and alloys of casting metal (cast alloy).

3. Casting processing and testingThe casting process includes the removal of foreign body core and the casting surface, removal pouring riser, relief grinding burrs and other projections as well as thermal treatment, shaping, rust prevention, rough finish and so on.

Introduction of Casting Process


Taizhou Sanjian Mould Co., Ltd. is belong to Zhejiang Hengda Plastic Mould Co.,Ltd, located in Huangyan, Zhejiang, known as "China mold town". Traffic convenient, our company is 130km east of Ningbo Port, 17 km south of Huangyan Airport, 1 km far from Bus Terminal , and 1 km north of highway exit.

We are specialized in aluminum die-casting, injection mold design, manufacturing and production and processing. Our main designs are auto series, home appliance series and daily series. Having strong mold development and design ability, from our establishment, we use advanced technology of CAD / CAM / CAE design, introduce large and medium-sized CNC machining centers and various CNC EDM machine to make the production and manufacturing.

Having the business philosophy of "first-class quality, reasonable price and credible service" and the idea of “Today's quality is tomorrow's market", we continuously improve our product quality, and has established a long-term cooperation relations with many well-known companies at home and abroad and all praise highly of our quality and service.

Sanjian is willing to be a friend and the cornerstone of all companies and provide new technology along with excellent quality to service for the cause of China's industrial and wholeheartedly welcome new and old friends to visit!

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introduction of die casting process casting.pdf · introduction of die ... to typical machining...

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